The present invention relates to the technical field concerning packaging articles wound in rolls, e.g. articles of paper and the like.
In particular, the invention relates to a conveying device aimed at working in a machine for packaging roll articles and the like.
Known automatic packaging machines wrap for articles in rolls with a sheet of heat-sealing material, e.g. polythene.
The packages usually include two, four or more rolls arranged in one or more layers.
According to a known solution applied to the packaging machines, rolls to be packed are fed by a conveying device including a series of carriages, which are spaced out and fastened to chain conveying means operated stepwise along an endless path defined by guides of the carriages.
The carriages include a plurality of pushing prongs or arms, which define, between each pair of adjacent carriages, holding seats for packs of rolls to be packaged.
While being introduced in the above mentioned holding seat, located at a suitable working station of the machine, the pack of rolls strikes against a sheet of heat-sealing material, so as to become partially wrapped.
Suitable folding means complete the wrapping of the pack of rolls with the heat-sealing material sheet.
The above mentioned carriages include heads, facing each other and equipped, along their sides, with ball bearings, which move inside guides defining the above mentioned endless path of the conveying means.
In their lower part, the carriages heads have means for fastening to the links of the conveying means.
The pushing prongs are situated on each carriage, suitably spaced apart.
The number of pushing prongs on each carriage changes in relation to the number of rolls to be packaged in each pack. In order to obtain a balanced situation during the pushing step, usually at least a pair of pushing prongs are necessary on each carriage for packages formed by e.g. two rolls, placed side by side.
The packs include one or more layers of rows of rolls; each row includes one or more rolls, in the latter case, the rolls of each row are coaxial and drawn close to the heads.
The axial dimension of the rows define the length of the pack. When the packages size is to be changed, consequently, also the length of the pack must be changed, and it is necessary to substitute all the carriages on the line with other carriages, suitable for new dimensions of the packages to be formed.
In order to do so, it is necessary to remove a suitably removable element of the guide, and to operate stepwise the conveying means with low speed to release and remove, one by one, the carriages to be substituted and mount the carriages adapted to the new working cycle.
Finally, it is necessary to adjust manually the additional means of the conveying device, such as means acting as stops for the moving rolls.
The operations needed for size change require a lot of time, as well as suitably trained staff.
Moreover, it is necessary to store additional sets of carriages in a magazine, which results in bigger number of mechanical parts and consequently, increases the costs and space required for a magazine.
The document U.S. Pat. No. 5,465,550 describes a conveying device which includes carriages equipped with removable prongs for pushing rolls.
In this case, the prongs are fastened to two parallel stems which constitute the carriages in the regions of suitable connection seats.
When it is necessary to change the size of packages of rolls, it is enough to disengage the pushing prongs from the carriages, by simply rotating them, with respect to carriages, and repositioning them according to the characteristics of the new working cycle products.
In some cases, it is necessary to increase the number of pushing prongs for each carriage, to maintain stable the dragging operation.
The above mentioned device avoids the necessity of a bigger magazine, yet it requires a long out-of-working time to remove, adjust and reposition the pushing prongs.
The object of the present invention is to resolve the above mentioned problems by proposing a conveying device, in which a simple and rapid changeover can be performed in accordance to the change of the pack length, in machines for packaging rolled articles and the like.
Another object of the present invention is to propose a conveying device, which does not require additional sets of mechanical parts, necessary for size changeover, to be held in a magazine.
A further object of the present invention is to propose a conveying device, which is very simple and functional, as well as versatile and used for different types of articles to be packaged.
The above mentioned objects are obtained, in accordance with the contents of the claims, by means of a conveying device for machines for packaging articles in rolls and the like, the conveying device including:
conveying means moved stepwise along an endless path, in a forward movement direction;
a series of spaced out carriages fastened to said conveying means and disposed in pairs, each pair of said pairs of said adjacent carriages defining holding seats for respective groups of articles to be packaged in a single pack with a sheet of a wrapping material;
each carriage of said carriages including:
gliding means fastened to said conveying means crosswise to said forward movement direction of said conveying means;
slide means slidingly mounted on said gliding means and located in a selected position along said gliding means of said carriages;
a series of pushing prongs extending, perpendicular to said conveying means, from said slide means;
means for adjusting said pushing prongs on said carriages by operating said slide means to move to a new selected position along said gliding means.